1. Field of the Invention
Embodiments of the present invention generally relate to backlit displays and more particularly to gradually dimming backlit display.
2. Description of the Related Art
Laptop computers are typically powered from rechargeable batteries. The length of operation a user can expect from a fully charged battery (i.e., battery life) is generally proportional to the storage capacity of the battery. Advances in battery technologies have resulted in rechargeable batteries (e.g., nickel-cadmium and lithium-ion batteries) with greater storage capacities, resulting in extended battery life. However, in an effort to further extend battery life, laptop computer manufacturers also strive to reduce power consumption.
Power consumption of backlit liquid crystal displays (LCDs) may account for a large portion of overall power consumption of a laptop computer. Conventional approaches to reducing power consumption of a backlit LCD are typically limited to reducing an amount of backlighting (i.e., dimming) in a single, relatively large, step. For example, a laptop computer may be configured to dim the backlighting by a fixed percentage (e.g., 20%) in response to detecting a power supply has been unplugged from an AC power supply and that the laptop computer is being powered from the battery. As another example, a laptop computer may be configured to trigger the dimming in response to detecting a predetermined period of inactivity (e.g., no keyboard or mouse activity), which may indicate the user is not present and/or not working with the laptop computer.
In both of these examples of dimming, however, because the level of backlighting is reduced in a single step, the dimming may be highly noticeable to a user. In the event that the user is present, the noticeable dimming may be a source of distraction. In some cases, to reduce the likelihood of the dimming occurring while the user is present, the user may set the period of inactivity that triggers the dimming to an excessively high amount or disable the dimming entirely. As a result, the backlighting may remain at full scale longer than necessary and optimum reductions in power consumption may not be achieved, thus reducing battery life.
Accordingly, what is needed is an improved method for dimming LCD backlighting that is less noticeable to a user.